赤琥珀螺线粒体全基因组测定与系统发育关系的研究

旨在通过高通量测序技术获得赤琥珀螺（Succinea erythrophana）线粒体基因组全序列，对其结构及组成特征进行分析，并结合NCBI数据库已公布的琥珀螺科及柄眼目物种序列，以最大似然法和贝叶斯法分别进行系统发育分析。结果显示：①赤琥珀螺线粒体基因组全长 14 023 bp（GenBank No.ON533899），由37个基因和一段富含AT的非编码控制区组成，有20处基因间隔，13处基因重叠。A＋T平均含量为77.3%，表现出明显的AT偏向性。基因的排列顺序、结构与组成、密码子使用情况与琥珀螺科已报道种类相似。 ②除tRNA-Phe、tRNA-His、tRNA-Ser1、tRNA-Ser2外，其余 tRNAs呈典型三叶草结构。③Ka/Ks选择压力分析显示其受到纯化选择作用。④系统发育研究揭示赤琥珀螺与同属的腐败琥珀螺（Succinea putris）亲缘关系最近，然后与同科其他物种形成姐妹群关系。

Complete Mitochondrial Genome Sequencing and Phylogeny Analysis of Succinea erythrophana

In this study,we obtained the complete mitochondrial genome sequence of Succinea erythrophana by high-throughput sequencing,and analyzed its structural and compositional features,and performed phylogenetic analyses using maximum likelihood (ML) and Bayesian inference (BI) methods (mtDNA sequences of three species of Succineidae and some species of Stylommatophora used in this paper downloading from NCBI).The results showed that:①The complete mitochondrial genome of Succinea erythrophana was 14 023 bp in length (GenBank No.ON533899),consisting of 37 genes and a segment of AT-rich non-coding control region,with 20 gene spacings and 13 gene overlaps.The average A+T was 77.3%,showing a significant AT bias.The order of gene arrangement,structure and composition,and codon usage were similar to those of the reported species in the Succineidae. ②The secondary structure of most tRNAs in Succinea erythrophana showed a typical cloverleaf structure except for tRNA-Phe,tRNA-His,tRNA-Ser1,and tRNA-Ser2.③Ka/Ks selection pressure analysis of Succinea erythrophana showed that it was subject to purifying selection.④Phylogenetic studies showed the closest relatives of Succinea erythrophana and Succinea putris,which then formed sister groups with other species of the same family.